1. Field of the Invention
The present invention relates to an integrated system for automatically providing the proper conditions to make linearity of measurements of fiber optic power meters.
2. Description of the Related Art
An optical loss test set (OLTS) consists of an optical power meter and an optical power source. Fiber optic communications systems typically use 850-nm or 1300-nm optical sources for multimode fiber optic networks, and 1310-nm or 1550-nm sources for single mode fiber optic networks. The OLTS power sources also produce optical signals at these wavelengths, and the optical power meter is calibrated to measure the power at each of these wavelengths. The OLTS is capable of making both absolute and relative power measurements. However, the most common measurement of interest taken by the OLTS is the relative power measurement. The typical OLTS provides a measurement range of at least 60 dB in most cases, and in some cases can exceed 100 dB.
In order to provide accurate measurements, an OLTS must be properly calibrated. The calibration of OLTSs is an issue that has been standardized by recognized standards organizations. For example, the National Institute of Standards and Technology (NIST), the Telecommunications Industry Association (TIA), and the International Electrotechnical Committee (IEC) have adopted standardized procedures for calibrating the several measurement parameters of the OLTS. The linearity of the optical power meter is a parameter of great importance as it determines the accuracy of the relative power measurements made by the OLTS. In order to calibrate the linearity of an optical power meter, the linearity must be measured to verify that the measurements made by the optical power meter are within specified tolerances.
Conventional optical power meter linearity measurement requires manual setup and operation, which is time-consuming and expensive. Alternatively, fully automated systems are available for performing optical power meter linearity measurement on high-end optical power meters that have control and measurement interfaces. However, lower-end optical power meters, such as handheld optical power meters, do not typically have such control and measurement interfaces. A need arises for a more automated technique for optical power meter linearity measurement for lower-end optical power meters, such as handheld optical power meters, which reduces the time and expense needed for linearity calibration.